Abstract
Abstract Background and objectives: Cognitive control is a term used about ways of processing information and regulating behavior, and the locus coeruleus – noradrenergic (LC-NA) system is thought to have an important role in the neural network allocating mental resources. This study aimed at affecting the balance between a proactive and a reactive cognitive control mode. The hypothesis was that the participants would use a reactive control mode with increased cognitive load. The second aim of the study was to see how cognitive load affects activity in the LC-NA system, hypothesized to elicit a load dependent LC-NA activation. Method: Twenty students performed the AX Continuous Performance Task (CPT), a dual response task testing cognitive control. Trials switched between single and dual cue identities to manipulate cognitive load. Pupillometry was used to measure changes in pupil diameter, an indicator of LC – NA activity. Response times, error rates and pupil dilation before and after response were analyzed. Results: The study showed that the increased cognitive load in the dual cue conditions had an impact on the participants, with higher error rates, longer response times and increased pupil dilation after response seen on the trials with two cue identities. Conclusions: The experimental manipulations had an effect on the participants, but not in a distinct reactive direction. This may be due to the experimental paradigm s unintended effect on spatial orientation in the dual cue paradigm, possibly eliciting more proactive control on these trials.